Interaction of a Streamwise Vortex with a Blade Tip Vortex

2006 ◽  
Vol 43 (6) ◽  
pp. 1956-1958 ◽  
Author(s):  
T. Lee ◽  
Y. Adukesem
Keyword(s):  
Streamwise Vortex ◽  
Tip Vortex ◽  
Blade Tip

Erratum: Interaction of a Streamwise Vortex with a Blade Tip Vortex

2007 ◽  
Vol 44 (2) ◽  
pp. 702-702
Author(s):  
T. Lee ◽  
Y. Aboelkassem
Keyword(s):  
Streamwise Vortex ◽  
Tip Vortex ◽  
Blade Tip

Investigation of Helicopter Rotor-Blade-Tip-Vortex Alleviation Using a Slotted Tip

AIAA Journal ◽  
2004 ◽  
Vol 42 (3) ◽  
pp. 524-535 ◽  
Author(s):  
Yong Oun Han ◽  
J. Gordon Leishman
Keyword(s):  
Rotor Blade ◽  
Tip Vortex ◽  
Helicopter Rotor ◽  
Helicopter Rotor Blade ◽  
Blade Tip

Investigation of the Blade Tip Clearance Effects on Performance and Stability of a Mixed-Flow Pump: High Speed Camera Recordings of the Flow Structures, Local Measurements and Numerical Simulation

2015 ◽  
Author(s):  
Alberto Serena ◽  
Lars E. Bakken
Keyword(s):  
High Speed ◽  
Detailed Comparison ◽  
Performance Comparison ◽  
Tip Clearance ◽  
Tip Vortex ◽  
High Speed Camera ◽  
Tip Leakage Flow ◽  
Quality Video ◽  
Local Measurements ◽  
Blade Tip

The tip leakage flow affects turbomachines performance generating losses and reducing the effective blading; in addition, unsteady phenomena arise, negatively influencing the machine stability. In this paper, an overview of the existing models is presented. Local measurements of the pressure pulsations, visual flow observations and high quality video recordings from a high speed camera are performed in a novel pump laboratory, which provides the desired visualization of the rotating channels, and allows to study the fluctuating and intermittent nature of this phenomenon, and detect any asymmetry among the channels. A detailed comparison of the vortex tip structure for various tip clearances and with a whole set of numerical simulations finally completes the analysis. The three main focus areas are: tip vortex location, structure and evolution, performance comparison between shrouded and open impeller, at different tip clearance sizes, and study of the rotating instabilities.

Numerical investigation of blade-tip-vortex dynamics

2018 ◽  
Vol 9 (3) ◽  
pp. 373-386 ◽  
Author(s):  
Kurt Kaufmann ◽  
C. Christian Wolf ◽  
Christoph B. Merz ◽  
Anthony D. Gardner
Keyword(s):  
Numerical Investigation ◽  
Vortex Dynamics ◽  
Tip Vortex ◽  
Blade Tip

Near Wake Regime Study on Wind Turbine Blade Tip Vortex

2019 ◽  
Author(s):  
Ojing Siram ◽  
Niranjan Sahoo
Keyword(s):  
Wind Turbine ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Flow Condition ◽  
Pitch Angle ◽  
Tip Vortex ◽  
Near Wake ◽  
Helical Vortex ◽  
Blade Tip ◽  
Blade Pitch Angle

Abstract In the present research article results on wind turbine blade tip vortex have been presented, the measurements have been done behind a model scale of horizontal axis wind turbine rotor. The rotor used for flow characterization is a three-bladed having NACA0012 cross-section, the study has been performed for low range tip speed ratio of 0–2 and wind speeds range of 3–6 m/s. The investigation has been conducted specifically to near wake regime, which is often expressed as the region of regular helical vortex structures. Although this nature of regular helical vortex pattern has always been a question of debate with respect to changes in the flow condition, rotor geometry and point of measurements. A systematic experiment was done mainly on the frequency of vortex shedding through hot-wire anemometry (HWA), and the corresponding frequency is express in terms of Strouhal number. Present article work within near wake regime includes tip vortex shedding stability analysis for different blade pitch angle and flow condition. From the systematic experimental observation, the evaluated data indicate that the Strouhal number has an incremental trend when the blade pitch angle is close to 40°, and above it inconsistency in frequency response is observed.

Experimental Investigation of the Flow Field of a Ceiling Fan

Volume 3 ◽  
2004 ◽  
Author(s):  
Ankur Jain ◽  
Rochan Raj Upadhyay ◽  
Samarth Chandra ◽  
Manish Saini ◽  
Sunil Kale
Keyword(s):  
Experimental Investigation ◽  
Energy Consumption ◽  
Flow Field ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Tip Vortex ◽  
Optimal Designs ◽  
Tropical Regions ◽  
Fundamental Understanding ◽  
Blade Tip

A ceiling fan is the predominating comfort provider in tropical regions worldwide. It consists of an assembly of an electric motor with 3–4 blades suspended from the ceiling of a room. Despite its simplicity and widespread use, the flow induced by a ceiling fan in a closed room has not been investigated, and sub-optimal designs are in wide use. There is vast potential for energy conservation and improved comfort by developing optimized fan designs. This work develops a fundamental understanding of the flow characteristics of a ceiling operating inside a closed room. Using smoke from thick incense sticks, the flow field created by the ceiling fan is visualized. In most regions, the flow is periodic and three-dimensional. Vortices are seen to be attached to the blade tip and hub, which reduces downward flow and increases energy consumption. Only the middle 75% of blade actually pushes the air downwards, and the comfort region is limited to a cylinder directly under the blades; velocities in this region were measured with a vane anemometer. Winglets and spikes attached to the blade tip disrupted the tip vortex, and increased downflow by about 13% without any increase in power consumption.

Blade tip vortex measurements on actively twisted rotor blades

2017 ◽  
Vol 58 (5) ◽  
Author(s):  
André Bauknecht ◽  
Benjamin Ewers ◽  
Oliver Schneider ◽  
Markus Raffel
Keyword(s):  
Rotor Blades ◽  
Tip Vortex ◽  
Blade Tip

scholarly journals Experimental investigation of a rotor blade tip vortex pair

2021 ◽  
Author(s):  
Dominic Schröder ◽  
Jorge Aguilar-Cabello ◽  
Thomas Leweke ◽  
Ralf Hörnschemeyer ◽  
Eike Stumpf
Keyword(s):  
Water Channel ◽  
Vortex Pair ◽  
Tip Vortex ◽  
Small Scale ◽  
Pressure Surface ◽  
Vortex Interactions ◽  
Rotating Blade ◽  
Blade Tip ◽  
Pair Generation ◽  
Helical Geometry

AbstractThis paper presents the results of an experimental study of two closely spaced vortices generated by a rotating blade with a modified tip geometry. The experiments are carried out in two water channel facilities and involve a generic one-bladed rotor operating in a regime near hover. It is equipped with a parametric fin placed perpendicular to the pressure surface near the tip, which generates a co-rotating vortex pair having a helical geometry. Based on previous results obtained with a fixed wing, a series of small-scale experiments is first carried out, to validate the method of vortex pair generation also for a rotating blade, and to obtain a qualitative overview of its evolution going downstream. A more detailed quantitative study is then performed in a larger facility at three times the initial scale. By varying the fin parameters, it was possible to obtain a configuration in which the two vortices have almost the same circulation. In both experiments, the vortex pair is found to merge into a single helical wake vortex within one blade rotation. Particle image velocimetry measurements show that the resulting vortex has a significantly larger core radius than the single tip vortex from a blade without fin. This finding may have relevance in the context of blade–vortex interactions, where noise generation and fatigue from fluid–structure interactions depend strongly on the vortex core size.

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